Balanced slide-valve



P. MGDERMOTT. BALANGBD SLIDE VALVE.

NQ. 312,144. Patented Feb. 10, 1885.

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NiTeD STATES ATENT GFFICE.

PATRICK MCDERMOTT, OF MEMPHIS, TENNESSEE.

BALANCED SLIDE-VALVE.

SPECIFICATION forming Application tiled August 20,1884. (No model.)

To all whom it may concern: 1

Be it known that I, PATRICK McDERMoTT, acitizen ofthe United States, residing at Memphis, in t-he county of Shelby and State of Tennessee, have invented certain new and useful Improvements in Balanced Slide-Valves for Steam-Engines, ot' which the following is aspecication. Y,

My invention relates to that class of slidevalves which are balanced by thecuse of a relief-plate, and provided between the surfaces of the said valve and relief-plate with a cavity for the reception of steam or water of condensation which may accumulate between said surfaces, said cavity having communication with the external atmosphere for permitting the escape of its accumulated contents.

My invention more particularly consists in improvements upon the balancing device described in my Letters Patent dated September 2, 1884.

In practically operating a balanced slidevalve having a relief plate, as described, it is 4found that the successful working of the device is somewhat detract-ed" from by the necessary imperfection of the connection between the'i'aces ofthe valve and the relietplate, resulting in the admission of more or less steam between said faces, with a consequent increase of the upward pressure on the` relief-plate- To remedy this evil a cavity or cavities is or are formed in the upper face ot' the valve or iu the lower face of the relief-plate, and provide means of discharge of the steam or water gathering therein to the outer air.

My invention consists in certain details in the construction ot' the mechanism for placing the cavities between the valve and relief-plate in communication with the external atmosphere, which are especially applicable to the devices shown and described in my patent above referred to.

In order that my invention may be more fully understood, I will proceed to describe it with reference to the accompanying` drawings, in which- Figure I is a vertical sectional view of the steam-chest and slide-valve of an engine embodying my invention. Fig. II is a perspective View of a D slide-valve of the ordinary double form, showing the cavities or depresl sions formed for the gathering of steam and water.

Although here shown applied to a double valve, the invention is plainly applicable to other kinds of balanced slide-valves.

In the drawings, l is the steam-chest; 2,the slide-valve; 3, its sea-t; 4, the relief-plate; 5, one ofthe supporting stems or rods of said plate; 6, one ot' the levers connecting said stems to the pistou-rod 7 ofthe balancing-engine 8, to which steam is admitted by the port 9 from the steam-chest. l() is the fulcrum of the lever 6, preferably adjustablein the manner described in my Letters Patent aforesaid. Cavities ll are formed, as shown, in the top ofthe valve, or in the bottom of the reliefplate, or in both, for gathering steam or water which may iind its way between the valve and plate. The stems 5 are made hollow, as shown. They are screwed into bosses 12 on the relief-plate, or otherwise fixed thereto, and have a series of holes near their base, through which the steam or water may pass to the interior ot' the stems, whence it is discharged into the outer air, or it may be led off in any desired manner.

Having thus described my invention, what I claim as new therein, and desire to secure by Letters Patent, is-

In combinatiomthesteam-chest 10, the valve 2, the relief-plate 4, the cavity ll between said valve and relief-plate, the balancing-engine 8, having the piston 7, the fulcrumed connecting-lever (i, and the hollow stem 5, communieating with the cavity Il and the external at mosphere, as and for the purpose set forth.

PATRICK MCDERMOTT.

Witnesses: f

I. BLOMBERG, SAML. M. MALLALrEN. 

